Secondary Organic Aerosol Formation From Isoprene Epoxides in the Pearl River Delta, South China: IEPOX‐ and HMML‐Derived Tracers

He, Quanfu; Ding, Xiang; Fu, Xiaogang; Zhang, Yuqing; Wang, Junqi; Liu, Yexin; Tang, Mingjin; Wang, Xinming; Rudich, Yinon

doi:10.1029/2017jd028242

Cited by 37 publications

(41 citation statements)

References 98 publications

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“…These values are within the range of 2-MG-OS measured in other urban locations (Nguyen et al, 2014;Rattanavaraha et al, 2016;Hettiyadura et al, 2019). However these concentrations are considerably higher than previously observed at two Chinese polluted regional sites 445 (Wang et al, 2018;He et al, 2018). At these locations, the ratio of the low-NO to high-NO isoprene OS tracer average concentrations was close to 1.5 (2-MT-OS:2-MG-OS; Beijing = 1.47, Wanqingsha = 1.57).…”

Section: -Methyl Glyceric Acid Os (2-mg-os)contrasting

confidence: 54%

“…Hettiyadura et al, 2019) but are higher than summer time observations at polluted regional background sites in China (Wang et al, 2018;He et al, 2018). The lower amounts of IEPOX-derived SOA results in an average AMS fC5H6O in Beijing during the APHH project of only 0.2 %, similar to observations in 390 other urban studies (Hu et al, 2015).…”

Section: -Methyltetrol Os (2-mt-os)mentioning

confidence: 54%

“…This represented only 3.8 % of the total OA, indicating there is limited formation of IEPOX under high-NOx conditions (average NOx = 21 ppb). He et al (2018) found higher concentrations of the low-NO isoprene SOA tracers (average = 121 ng m -3 ) than the high-NO iSOA tracers (average = 9 ng m -3 ) at a regional background site (Wanqingsha) situated within the heavily polluted Pearl River Delta Region.…”

mentioning

confidence: 79%

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Strong anthropogenic control of secondary organic aerosol formation from isoprene in Beijing

Bryant¹,

Dixon²,

Hopkins³

et al. 2019

Preprint

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Abstract. Isoprene-derived secondary organic aerosol (iSOA) is a significant contributor to organic carbon (OC) in some forested regions, such as tropical rainforests and the Southeast US. However, its contribution to organic aerosol in urban areas, with high levels of anthropogenic pollutants, is poorly understood. In this study we examined the formation of anthropogenic-influenced iSOA during summer in Beijing, China. Local isoprene emissions and high levels of anthropogenic pollutants, in particular NOx and particulate SO42−, led to the formation of iSOA under both high- and low-NO oxidation conditions, with significant heterogeneous transformations of isoprene-derived oxidation products to particulate organosulfates (OSs) and nitrooxy-organosulfates (NOSs). Ultra-pressure liquid chromatography coupled to high-resolution mass spectrometry was combined with a rapid automated data processing technique to quantify 31 proposed iSOA tracers in offline PM2.5 filter extracts. The co-elution of the inorganic ions in the extracts caused matrix effects that impacted two authentic standards differently. The average concentration of iSOA OSs and NOSs was 82.5 ng m−3, around three times higher than the observed concentrations of their oxygenated precursors (2-methyltetrols and 2-methylglyceric acid). OS formation was dependant on both photochemistry and sulfate available for reactive uptake as shown by a strong correlation with the product of ozone (O3) and particulate sulfate (SO42−). A greater proportion of high-NO OS products were observed in Beijing compared to previous studies in less polluted environments. The iSOA derived OSs and NOSs represented on average 0.62 % of the oxidised organic aerosol measured by aerosol mass spectrometry, but this increased to ~ 3 % on certain days. These results indicate for the first time that iSOA formation in urban Beijing is strongly controlled by anthropogenic emissions and results in extensive conversion to heterogeneous OS products.

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Section: -Methyl Glyceric Acid Os (2-mg-os)contrasting

confidence: 54%

Section: -Methyltetrol Os (2-mt-os)mentioning

confidence: 54%

mentioning

confidence: 79%

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Strong anthropogenic control of secondary organic aerosol formation from isoprene in Beijing

Bryant¹,

Dixon²,

Hopkins³

et al. 2019

Preprint

View full text Add to dashboard Cite

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“…However, organic compounds and inorganic salts often coexist with varying concentrations in the atmosphere. For instance, field studies have reported that the mass concentration of 2methyltetrols ranges from 1 to over 100 ng m −3 , while that of AS ranges from few to tens of micrograms per cubic meter (Schauer et al, 2002;Lewandowski et al, 2007;Kleindienst et al, 2010;Budisulistiorini et al, 2013;Xu et al, 2014;Hu et al, 2015). The mass concentration ratio of sulfate-to-2methyltetrols can vary greatly from ∼ 1.89 to ∼ 250.…”

Section: Introductionmentioning

confidence: 99%

Effect of inorganic-to-organic mass ratio on the heterogeneous OH reaction rates of erythritol: implications for atmospheric chemical stability of 2-methyltetrols

Lam

Wilson

et al. 2020

Atmos. Chem. Phys.

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Abstract. The 2-methyltetrols have been widely chosen as chemical tracers for isoprene-derived secondary organic aerosols. While they are often assumed to be relatively unreactive, a laboratory study reported that pure erythritol particles (an analog of 2-methyltetrols) can be heterogeneously oxidized by gas-phase OH radicals at a significant rate. This might question the efficacy of these compounds as tracers in aerosol source-apportionment studies. Additional uncertainty could arise as organic compounds and inorganic salts often coexist in atmospheric particles. To gain more insights into the chemical stability of 2-methyltetrols in atmospheric particles, this study investigates the heterogeneous OH oxidation of pure erythritol particles and particles containing erythritol and ammonium sulfate (AS) at different dry inorganic-to-organic mass ratios (IOR) in an aerosol flow tube reactor at a high relative humidity of 85 %. The same reaction products are formed upon heterogenous OH oxidation of erythritol and erythritol–AS particles, suggesting that the reaction pathways are not strongly affected by the presence and amount of AS. On the other hand, the effective OH uptake coefficient, γeff, is found to decrease by about a factor of ∼20 from 0.45±0.025 to 0.02±0.001 when the relative abundance of AS increases and the IOR increases from 0.0 to 5.0. One likely explanation is the presence of dissolved ions slows down the reaction rates by decreasing the surface concentration of erythritol and reducing the frequency of collision between erythritol and gas-phase OH radicals at the particle surface. Hence, the heterogeneous OH reactivity of erythritol and likely 2-methyltetrols in atmospheric particles would be slower than previously thought when the salts are present. Given 2-methyltetrols often coexist with a significant amount of AS in many environments, where ambient IOR can vary from ∼1.89 to ∼250, our kinetic data would suggest that 2-methyltetrols in atmospheric particles are likely chemically stable against heterogeneous OH oxidation under humid conditions.

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“…1b). Hofzumahaus et al (2009) observed extremely high OH concentrations in the PRD and proposed a recycling mechanism that increases the stability of OH in the air of polluted regions. All of the abovementioned results indicate a high atmospheric oxidative capacity in the PRD, as O 3 , NO x , and OH are intimately linked in atmospheric chemistry.…”

Section: Introductionmentioning

confidence: 99%

Impact of anthropogenic emissions on biogenic secondary organic aerosol: observation in the Pearl River Delta, southern China

et al. 2019

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Secondary organic aerosol (SOA) formation from biogenic precursors is affected by anthropogenic emissions, which are not well understood in polluted areas. In this study, we accomplished a year-round campaign at nine sites in polluted areas located in the Pearl River Delta (PRD) region during 2015. We measured typical biogenic SOA (BSOA) tracers from isoprene, monoterpenes, and β-caryophyllene, as well as major gaseous and particulate pollutants and investigated the impact of anthropogenic pollutants on BSOA formation. The concentrations of BSOA tracers were in the range of 45.4 to 109 ng m −3 with the majority composed of products from monoterpenes (SOA M , 47.2 ± 9.29 ng m −3 ), isoprene (SOA I , 23.1 ± 10.8 ng m −3 ), and β-caryophyllene (SOA C , 3.85 ± 1.75 ng m −3 ). We found that atmospheric oxidants, O x (O 3 plus NO 2 ), and sulfate correlated well with later-generation SOA M tracers, but this was not the case for first-generation SOA M products. This suggested that high O x and sulfate levels could promote the formation of later-generation SOA M products, which probably led to the relatively aged SOA M that we observed in the PRD. For the SOA I tracers, both 2-methylglyceric acid (NO/NO 2channel product) and the ratio of 2-methylglyceric acid to 2-methyltetrols (HO 2 -channel products) exhibit NO x dependence, indicating the significant impact of NO x on SOA I formation pathways. The SOA C tracer was elevated in winter at all sites and was positively correlated with levoglucosan, O x , and sulfate. Thus, the unexpected increase in SOA C in wintertime might be highly associated with the enhancement of biomass burning, O 3 chemistry, and the sulfate component in the PRD. The BSOAs that were estimated using the SOA tracer approach showed the highest concentration in fall and the lowest concentration in spring with an annual average concentration of 1.68 ± 0.40 µg m −3 . SOA M dominated the BSOA mass all year round. We also found that BSOA correlated well with sulfate and O x . This implied a significant effect from anthropogenic pollutants on BSOA formation and highlighted that we could reduce BSOA by controlling the anthropogenic emissions of sulfate and O x precursors in polluted regions.

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Secondary Organic Aerosol Formation From Isoprene Epoxides in the Pearl River Delta, South China: IEPOX‐ and HMML‐Derived Tracers

Cited by 37 publications

References 98 publications

Strong anthropogenic control of secondary organic aerosol formation from isoprene in Beijing

Strong anthropogenic control of secondary organic aerosol formation from isoprene in Beijing

Effect of inorganic-to-organic mass ratio on the heterogeneous OH reaction rates of erythritol: implications for atmospheric chemical stability of 2-methyltetrols

Impact of anthropogenic emissions on biogenic secondary organic aerosol: observation in the Pearl River Delta, southern China

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